Locking device for take-up reel



June 19, 1962 N. A. APPLETON LOCKING DEVICE FOR TAKE-UP REEL Filed Dec. 24, 1959 ,T'L L MQ, Val-k QATTQWQEY/ United States. Patent Ofifice 3,039,717 Patented June 19, 1962 3,039,717 LOCKING DEVICE FOR TAKE-UP REEL Norton A. Appleton, Northhrook, 111., assignor to Appleton Electric Company, Chicago, 111., a corporation of Illinois Filed Dec. 24, 1959, Ser. No. 861,865 1 Claim. (Cl. 242-1673) The present invention relates to improvements in takeup reels of the type comprising a drum, carrying a cord or cable, journaled on a shaft which is mounted in a frame or housing, with a main drive spring fixed between the drum and the shaft for rewinding cord which has been pulled out from the drum.

More specifically, the present invention relates to a take-up reel assembly of the foregoing type having, as an improvement, a novel releasable locking device for effecting automatic locking of the reel against rewinding when a desired length of cord has been run out.

In take-up reel assemblies such as described herein, releasable locking devices are used to effect automatic locking of the cord or hose which has been run out of the reel. Such locking devices are releasable in response to a short pull on the unwound cord and thereupon permit the entire length of cord to be automatically rewound under the action of the main rewind loading spring.

The present invention is primarily concerned with a new and improved releasable locking device, and has, as its general object, the provision in a take-up reel assembly of the type set forth of a novel improved locking device which comprises a simple, single pivoted dog construction which is effective in any position, both vertical and horizontal, of the take-up reel.

Another object of the invention is to provide an improved single pivoted one piece locking device which is rugged, foolproof and reliable in operation and is susceptible of production by mass production means.

Other objects and advantages will become apparent as the following description proceeds taken in connection with the accompanying drawings wherein:

FIGURE 1 is a vertical elevation view of a take-up reel embodying the present invention with a portion of the housing cut away to expose the features of the present invention.

FIG, 2 is an enlarged plan view of a locking device spring construction embodying the present invention, and taken substantially in the plane of line 22 of FIG. 4.

FIG. 3 is a perspective view of a locking device, including a dog and biasing spring therefore, embodying the present invention.

FIG. 4 is a section view taken substantially in the plane of line 44 of FIG. 1 and illustrating the locking device in the position it occupies when the reel is rotating.

FIG. 5 is a view similar to FIG. 4 but showing the locking device locking the reel against rotation tending to rewind the cord.

While a certain illustrative embodiment has been shown in the drawing and will be described below in considerable detail, it should be understood that there is no intention to limit the invention to the specific form disclosed. On the contrary, the intention is to cover all modifications, alternative constructions, equivalents and uses falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more specifically to the drawing, the invention is there shown embodied in an illustrative take-up reel assembly which in the present instance comprises a housing attached to a supporting flange 12. Preferably, the housing 10 is defined by means of a pair of opposed dished sheet metal shells 14, having their contacting peripheral portions mechanically engaged in any suitable manner. One means for joining the two dished shells includes the use of an annular channel shaped member 16 having in-turned flanges which are mechanically engaged to the inside surface of the peripheral edges of housing shells such as by spot welding.

Journaled in a socket 18 mounted centrally on the inner surface of one of said dished walls 15 and extending through a central aperture through the opposite dished wall 14 is a drum supporting shaft 19. In the present device, the extremity of the shaft extending through the housing wall 14 is provided with an annular collar 20 which abuts the inner surface of the housing wall 14 and thereby prevents the shaft from sliding in a longitudinal direction with respect to the housing.

Journal ed on the supporting shaft 19 but restrained against axial movement therealong is a reel or drum 21 adapted to receive a length of hose or cord 22 and to store the same in convolutions thereon. In the present instance the drum is provided with a length of electrical grounding cord 22 having a free end which extends from the drum tangentially passing out of the housing via an enlarged circumferential aperture 24. The opening 24 is of a suitable size to allow free passage of the cord 22 but is small enough to intercept a resilient stop (not shown) attached to the free end of the cord in a manner well known in the art. The edges of the opening 24 are preferably provided with a suitable bushing 26 to prevent chafing of the cord. The drum 21 is biased toward its rewound position by means of a spring such as a relatively heavy spirally wound clock spring 28 fixed to the drum at one end and having its other end connected to the shaft 19 Operatively associated with the drum and the housing is a releasable locking mechanism 30 embodying the present invention. The mechanism 3% enables a predetermined length of cord to be unwound and the drum subsequently locked in such position, the locking mechanism 30 also permitting the rewinding of the cord on the drum under the action of the spring 28 after a short further unwinding movement of the cord 22 and a subsequent release of tension on the cord.

Also associated with the drum 21 and the housing 10 is a sliding contact assembly 32 adapted to provide an electrical connection between a suitable terminal (not shown) on the housing and the end of the cord 22.

In accordance with the present invention, for purposes of automatically locking the reel against rewinding when a desired length of cord has been withdrawn from the drum and for releasing the drum, in response to a short pull on the unwound cord so that the cord may be rewound as the drum rotates, the locking device 35) embodying the invention contemplates a centrifugally actuated dog 34, pivotally mounted by means of a pin 35 on one side of the drum 21, and engageable with a flat, disclike ratchet plate 36 fixed on the shaft 19 by means of a. pin 37 on the shaft engaged in a corresponding radial slot 37a in the plate 36. The ratchet plate is formed with a plurality of spaced apertures or notches 38 in its peripheral edge into which the dogengages. In order to engage with the ratchet plate yet be readily releasable therefrom upon a short pull on the cord, the dog 34is preferably formed as a generally elongated member swingably supported, at a point adjacent one of its ends, on the pin 35, and is formed at its opposite end with a smoothly rounded projecting portion or tongue 39. The notches 38 in the ratchet plate 36 are preferably rounded to enable the tongue 39 to engage with the ratchet plate and hold the drum against rotation by the main drive spring, yet readily slide out of the notch in which it is engaged upon a short pull on the cord.

It will be readily understood that, as the drum rotates at a speed above a certain minimum, the tongue end of the dog will swing outwardly about the pin 35 because of the centrifugal force exerted on it, and, when the reel is rotating at a speed below this minimum speed, the dog will drop into engagement with the ratchet plate 35 and engage in a notch 38 thereon. The minimum drum speed which will hold the dog free of the ratchet depends primarily upon the weight of the dog and the point at which it is pivoted on the drum, in addition to other forces exerted on it as will become apparent as the description proceeds.

The locking device embodying the present invention employs only one dog 34 pivotally mounted on the drum 21, and yet is efiective in all positions of the take-up reel. In other words, the novel locking device is efiective when the reel is in either a horizontal or a vertical position or in any inbetween position, and is effective when the reel is mounted on either a floor or a ceiling member. To this end, the locking device embodying this invention includes a particularly constructed spring device 41 which is capable of biasing the dog against the pull of gravity thereon and yet which does not interfere with the action of centrifugal force on the dog as the drum rotates at a speed above the necessary minimum to hold the tongue 39 away from engagement with the ratchet 36. One illustrative spring device 40 capable of biasing the dog 34 into engagement with the ratchet 36 without interfering with the centrifugal operation thereof, is shown in the drawings and comprises a helically wound coil spring body 41 made of a light weight but resilient material having a pair of relatively long thin legs 42, 43 of unequal length extending one from each end thereof. The shorter one of the legs 42 of the spring acts against the drum while the other leg 43 acts on a shoulder 45 defined on the dog 34 at the end thereof opposite from the tongue 39 so that the dog 34 is urged to swing about the pivot pin 35 to engage the tongue 39 in a notch 38 in the ratchet 36. The legs 42, 43, as mentioned, are relatively long, this being with respect to the diameter of the spring coil and to the distance between the point of engagement of the longer leg 43 with the dog shoulder 45 and center of the dog pivot pin 35. An illustrative spring device 40 of the character described is formed of light gauge phosphorous-bronze Wire with a coil 41 containing approximately /2 coils of wire with the legs being approximately 3 /2 to 6 times as long as the diameter of the coil or the distance defined between .the point of contact of the spring leg 43 with the dog shoulder 45 and the point of rotation of the dog on the drum, and with the Weight of the dog being proportioned accordingly.

The coil 41 of the spring device 40 is mounted on a pin 46 fixed on the side wall of the drum 21, and both the spring device 40 and the dog 34 are held on their respective pins by a plate-like wall member 48 of a ratchet cup 49 fixed onto the drum wall 21 and surrounding the spring device 40, dog 34 and ratchet plate 36. To engage the drum wall the shorter leg 42 of the spring is formed with an outwardly extending step-like portion 50 which projects through an adjacent hole 51 in the drum wall 21 as shown in FIG. 2. The other and longer leg 43 of the spring is formed with an inturned portion 52 which engages the shoulder 45 formed on the dog.

Using the above defined spring and dog construction, with the members proportioned with respect to each other to provide the desired biasing force on the dog, the free floating effect of the spring device to avoid hinderance with centrifugal forces on the dog is achieved by arranging the elements all on the circumference of a single circle having its center on the axis of rotation of the drum and having a radius, indicated at A on FIG. 5, slightly larger than the radius of the outer edge of the ratchet plate 36. More specifically, referring to FIG. 5, the desired free floating spring force with the above described spring device is obtained by locating the dog pivot axis, the spring coil pivot axis, the point of engagement of the shorter spring leg with the drum, and the point of engagement of the longer spring leg with the dog, all on a common circle having its center at the axis of rotation of the drum and having a radius A such that the dog tongue normally rests lightly on the outer peripheral edge of the ratchet. To avoid undesired friction effects which would restrict the freedom of movement of the dog, the ratchet cover plate wall 48 is spaced from contact with both the dog and spring. This is accomplished by providing bosses 54 on the dog 34 so that the latter is held against axial movement on the pin between the plate 48 and the drum wall 21.

With a reel and locking device constructed in this manner, the locking dog is urged against the ratchet plate with sufiicient force to overcome any force of gravity tending to pull it away from the ratchet, while the dog remains substantially free to swing outwardly under centrifugal forces thereon when'the drum is rotating above a minimum speed so that the cord can be rewound onto the drum.

1 claim as my invention:

A take-up reel including a cord carrying drum journaled on a shaft mounted in a housing with a main drive spring operatively connected between the drum and the shaft for rewinding cord withdrawn therefrom, a locking device comprising a dog having means on one end defining a projection and means on the other end defining a shoulder, means adjacent said shoulder end of said dog pivotally mounting said dog on the drum, a ratchet plate mounted on said shaft and having defined in one edge thereof a plurality of spaced slots for receiving said projecting end of said dog, and a spring device comprising a coil portion having one long leg extending from one end thereof and one relatively short leg extending from the other end thereof and in substantially the same direction as said long leg, said spring coil being pivotally mounted on said drum at a point spaced from said dog pivot mounting with said short leg in fixed engagement with said drum and said long leg extending into operative engagement with said dog shoulder, said dog pivot axis, spring pivot axis and the points of engagement of the spring legs with the drum wall and the dog all being on the circumference of a common circle having as a center the axis of rotation of the drum and said do and spring device being constructed and arranged so that said spring exerts a force on said dog shoulder sufiicient to raise said dog projection end against the force of gravity without interfering with the movement of said dog under the centrifugal force thereon resulting from rotation of said drum.

References Cited in the file of this patent UNITED STATES PATENTS 1,403,340 Moors Jan. 10, 1922 1,624,053 Husted Apr. 12, 1927 2,105,469 Bosch Jan. 18, 1938 2,834,314 Moore May 13, 1958 

